A typical planer and thicknesser comprises a rectangular, box-like frame comprising a horizontal rectangular upper table and a base connected to each other along their longer sides by two side walls. The horizontal upper table is located directly above the rectangular base. A first aperture is formed by one of the shorter ends of the upper table and by the base and one end of each of the two side walls. Similarly, a second aperture is formed on the opposite side of the rectangular box frame by the other shorter end of the upper table and the other end of the base, together with the other ends of each of the side walls. A passage way connects the two apertures to each other.
The upper table is constructed from two rectangular sections, a front section and a rear section. The two sections of the upper table are constructed from single rectangular sheets of metal having smooth top surfaces. The top surface of the front section is parallel to the top surface of the rear section. Both the top surfaces are smooth so that a work piece can be slideably moved across their surfaces. The height of the front section can be adjusted relative to the height of the rear section. The two sections are separated by a slot.
A horizontal lower table is movably located within the passage way. The plane of the lower table is parallel to that of the upper table. The lower table is constructed as a single rectangular sheet of metal having a smooth top surface. The lower table extends through the full length of the passage way from the first aperture to the second aperture. The width of the table is slightly less than that the width of the passage way. The table is mounted in such a manner that it can be moved vertically upwards or downwards, the top surface of the table remaining horizontal at all times during this process.
A cutting drum is rotatably mounted between the two side walls in such a manner that its axis of rotation is perpendicular to the plane of the side walls and parallel to the planes of the upper and lower tables. The cutting drum can be rotatably driven by an electric motor mounted within the base. The axis of rotation of the cutting drum is located below the upper table.
A part of the periphery of the cutting drum along its length extends upwardly through the slot between the front and rear sections of the upper table.
Each of the two cutting blades are mounted within a groove of the cutting drum which runs along the length of the cutting drum in well known manner parallel to the axis of rotation. The cutting blades of the cutting drum can be used to cut work pieces in well known manner which are either slideably moved across the upper table in one direction or are slideably moved across the lower table in the other direction.
The cutting drum is located so that, as the cutting drum rotates, the maximum height of the cutting blades mounted within the cutting drum through the slot are approximately the same as the height of the rear section of the upper table, the height of the rear section being fixed relative to the frame.
Two drive rollers are mounted on either side of the cutting drum between the side walls in such a manner that their axes of rotation are parallel to that of the cutting drum. The two drive rollers are rotatably driven by the same electric motor which is used to drive the cutting drum. The function of the two drive rollers is to move any work pieces which are fed into the rectangular passageway across the lower table and to engage the cutting blades at their lowest point as the rotating cutting drum rotates.
A planer and thicknesser can be used in two different modes of operation.
In the first mode of operation, a work piece is slideably moved across the upper table in order to remove the surface of the work piece which is adjacent to the smooth top surface of the upper table. The height of the front section of the upper table determines the amount of material which is to be removed from the work piece. First, the height of the front section is adjusted so that the cutting action of the rotating drum removes the right thickness of material from the lower surface of the work piece. Next, the cutting drum is then rotatingly driven by the electric motor. While the cutting drum is rotating, the work piece is slideably moved across the front section of the upper table until it engages the cutting blades of the cutting drum as they rotate. The work piece is then pushed onto the rear section of the upper table across the rotating cutting drum. As the work piece passes over the rotating blades of the cutting drum, the cutting blades remove material from the underside of the work piece.
In the second mode of operation, a work piece is slideably moved across the smooth surface of the lower table in order to remove the top surface of the work piece. The height of the lower table within the passageway determines the amount of material which will be removed from the top surface of the work piece as it is passes through the passageway. First, the height of the lower table is adjusted so that the cutting action of the rotating drum removes the correct thickness of material from the top surface of the work piece. Next, the cutting drum is then rotatingly driven by the electric motor. While the cutting drum is rotating, the work piece is slideably moved across the lower table, until the upper surface of the work piece engages the cutting blades of the cutting drum as a cutting drum rotates. As the work piece passes under the cutting blades, the cutting blades remove material from the topside of the work piece. The two drive rollers, which are also being rotatingly driven by the electric motor, help move the work piece through the passageway.
However, there are a number of problems associated with existing designs of planer and thicknessers.
The object of the present invention is to improve the design and construction of the planer and thicknessers.